termios.4: Cross-reference stack(9) for STATUS

If the kernel is built without stack(9) (options STACK),
then the mentioned sysctl(8) kern.tty_info_kstacks will not be found.

MFC after:		3 days
Reviewed by:		kib, ziaee
Differential Revision:	https://reviews.freebsd.org/D54701

share/man/man4/termios.4

@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd June 28, 2020
+.Dd January 14, 2026
 .Dt TERMIOS 4
 .Os
 .Sh NAME
@@ -759,7 +759,9 @@ wait channel, the number of user and system seconds used,
 the percentage of cpu the process is getting, and the resident
 set size of the process.
 .Pp
-In case the
+In case the kernel has
+.Xr stack 9
+support configured and the
 .Xr sysctl 8
 variable
 .Va kern.tty_info_kstacks